Automatic processor for emulsion coated metal templates

ABSTRACT

Apparatus to develop sensitized emulsion coating on a metallic base sheet comprises: A. A SEQUENCE OF SHEET CONVEYING ROLLERS ROTATING TO CONVEY THE SHEET GENERALLY HORIZONTALLY IN A FORWARD DIRECTION AND WITH THE COATING EXPOSED VERTICALLY, B. TREATING MEANS TO DELIVER AND DIRECT DIFFERENT LIQUIDS INTO CONTACT WITH SAID COATING AT DIFFERENT STATIONS DURING SHEET FORWARD CONVEYANCE, C. AND MULTIPLE SQUEEGEES WHICH ARE SPACED IN SAID DIRECTION TO ENGAGE SAID COATING DURING SAID CONVEYANCE AND TO CONFINE SAID DIFFERENT LIQUIDS AT SAID DIFFERENT STATIONS DURING LIQUID CONTACT WITH SAID COATING.

0 Umted States Patent [1 1 [111 3,752,054 Scanian Aug. 14, 1973 AUTOMATIC PROCESSOR FOR EMULSION 3,545,364 12/1970 Reedy et al. 95194 R A E E L 3,583,805 6/1971 Tanaka 95/89 R Co M TAL T MP ATES 3,402,656 9/1968 Stocking 95/89 A [76] Inventor: Raymond J. Scanlan, 3029 Gainsborough D12, Pasadena, Primary Examiner kichard Moses 91107 Attorney-William W. Haefliger et a]. [22] Filed: Mar. 23, 1972 211 App]. No.: 237,459 [57] ABSTRACT Apparatus to develop sensitized emulsion coating on a metallic base sheet comprises: [52] U.S. Cl. 95/94 R, 9542985,}??? 3A2, a. a sequence of sheet conveying rollers rotating to 5 Int Cl 5 6 4 convey the sheet generally horizontally in a I O 0 a e I u I e e s I a 0 n I e I a I e I a I I e 0 I a a I n u c I I c 1 I I I I on d d t I d [58] Field of Search 95/94 R, 89R, 89 A, ;,},Z; an m h the mung expse 95/89 F; 271/52 b. treating means to deliver and direct different liquids into contact with said coating at different [56] Re'erences Cited stations during sheet forward conveyance,

UNITED STATES PATENTS c. and multiple squeegees which are spaced in said 3,608,464 9/1971 Harrell et al 95/89 R direction to engage said coating during said 3,635,144 1/ i972 Beck 95/89 R conveyance and to confine said different liquids at 1,973,749 9/1934 Dawson 271/5 said different stations during liquid contact with 3,120,794 2/l964 Gold 95/89 R said coating 3,552,293 1/1971 Cuthbert 95/89 A 3,593,641 7 1971 Adams et al. 95/89 R 6 Claims, 6 Drawing Figures oneleleieieie eieirenemi mug a; 6 3 is Patented Au 14, 1973 2 Sheets-Sheet 2 BACKGROUND OF THE INVENTION This invention relates generally to processing of metal templates to develop emulsion coatings thereon. More specifically, it concerns the provision of automatic processing apparatus capable of treating a sequence of templates, as for example washing and developing the emulsion coatings, and waterproofing them for permanent tooling and storage.

There is a need for simple, automatic apparatus capable of rapidly treating sensitized emulsion coatings on large metal templates as described, in order to achieve savings in cost and time. Such templates are for example used in industry for tooling purposes, i.e. as forms for delineating outlines or patterns on work pieces. To my knowledge, there has been no prior apparatus having the unusually advantageous construction and mode of operation characteristic of the present invention, or capable of achieving its unusally beneficial results.

SUMMARY OF THE INVENTION I It is a major object of the invention to provide automatic template processing equipment meeting the need referred to. Basically, the apparatus comprises a set of rollers rotating to convey the sheet generally horizontally forwardly and with the coating exposed vertically; treating means to deliver and direct different liquids into contact with the coating at different stations during sheet travel; and multiple squeegees spaced in the sheet travel path to engage the coating and confine the different liquids at the different stations. As will be seen, the rollers are typically spaced to drain excess liquid flowing off the sheet edges, and into collectors beneath the stations, developer liquid being recirculated from one collector to header ducting overlying one stationv Rinse liquid is typically supplied to wash the coating as the sheet passes through stations preceding and following the developer delivery station. Endless flexible traction means, as for example belts, are typically employed to drive the conveyor rollers, the latter supported to float on the belts, as will be seen.

The squeegees may advantageously comprise rollers defining the fore and aft limits of the different rinse and developer application stations, and may be carried to float vertically in response to sheet travel there beneath, whereby the liquid at each station is confined or dammed to drain off the sheet edges, as described, without carryover into the subsequent stations.

Finally, it is an object of the invention to provide means at subsequent stations to heat the sheet for drying the developer treated and rinsed emulsion coating, and to apply a protective layer over the dried emulsion. Narrow streams of air may also be directed at the sheet as it passes between such treating zones, as will be seen. I These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description and drawings, in which:

DRAWING DESCRIPTION FIGS. la and lb are side elevational view of different portions of an automatic processor embodying the invention; and

FIGS. 2-5 are vertical sections taken on lines 2-2, 3-3, 44 and 5--5 in FIGS. 1a and lb.

DETAILED DESCRIPTION In accordance with the invention, apparatus is provided as at 10 to develop sensitized diazo-type emulsion 11 (blue print or brown print type) coating a thin metallic base sheet or template 12. In general, that apparatus comprises a sequence of sheet conveying rollers rotating to convey the sheet generally horizontally in a forward direction with the coating 11 facing vertically; treating means to deliver and direct different liquids into contact with the coating at different stations during sheet forward conveyance; and multiple squeegees (as for example squeegee rollers) which are spaced in that direction to engage the coating during sheet advancement and to confine or dam the different liquids at the different stations during liquid contact with the coating.

In the illustrated embodiment, rollers 13 extend in horizontal sequence, with parallel axes 14. Trunnions 15 project axially at opposite ends of the cylindrical rollers and are loosely received in vertical slots 16 formed in vertical side plates 17. The latter are carried by horizontally extending members 18 supported by legs 19.

Conveyance of the sheet in the direction of arrow 20 and on the rollers 13 may be effected by driving the rollers in the unusually effective and simple manner illustrated. As shown, endless flexible traction means as for example belts 22, engage the undersides of the rollers at their opposite end portions 13a, so as to support the rollers in rotatably driven relation. In this regard, such support is characterized as floating in that up and down movement of the rollers is unrestricted, the weight of the rollers holding them downwardly against the belts. Slots l6 accommodate such floating, while the edges of plates 17 that define the slots restrain forward and rearward displacement of the rollers. Plates 17 also limit endwise movement of the rollers. Low friction, belt supporting tracks 23 are carried by angle members 18, and may consist of TEFLON strips. Additionally, it will be noted that the rollers are spaced apart in the sheet advancement direction to drain excess liquid flowing off the lateral edges 24 of the sheet, there being drip rings 25 on the rollers laterally outwardly of the sheet and inwardly of the belts and tracks to block laterally outward drainage of liquid on the rollers and onto the belts and tracks.

Referring back to FIG. 1 multiple liquid treating stations are generally indicated at 26, 27 and 28, station 26 defined between spaced squeegee rollers 29 and 30, stations 27 defined between spaced squeegee rollers 31 and 32, and station 28 defined between spaced squeegee rollers 33 and 34. Rollers 29-34 are also mounted to float vertically in accommodating relation with the sheet 12 advanced beneath them, over and by the rollers 13, frictional engagement of the squeezee rollers with the sheet serving to rotate them as required. The squeegee rollers outer surfaces may consist of elastomet, as may the surfaces of rollers 13. Trunnions 35 at the ends of the squeegee rollers loosely project in vertical guide slots 36 formed by upright fingers 37, as shown, for restricting the squeegee, rollers against longitudinal displacement while guiding their vertical floating movement.

At station 27, developer liquid is delivered from a sump source 38 via pump 39 and pipe 40 to header duct 41 directly overlying the path (12a in FIG. 3) of forward advancement of the sheet 12, and between squeegee rollers 31 and 32. Duct 41 carries multiple plastic spray outlet nozzles 42 spaced laterally to deliver sprays of developer liquid onto the emulsion coating on the sheet as it slowly advances. A solenoid controlled valve unit 43 in series with pipe 40 responds to tripping of a switch by lifting of the squeegee roller 31, thereby to pass developer liquid to duct 41 for spraying as described. A manual control valve 44 may also be used, as shown. Draining developer is collected in pan 47 for conduction via return pipe 48 to sump 38.

Rinse liquid, as for example water, is supplied from source piping 50 and risers 50a to headers 51 and 52 directly overlying the paths of forward advancement of the sheet at stations 26 and 28, respectively preceding and following station 27. Rinse liquid sprayed onto the underpassing sheet emulsion cleanses same and neutrallfies the emulsion, the waste rinse liquid draining off the sheet edges and into collector pans 54 and 55 for discharge to pipe 56. Solenoid controlled valve units 57 in series with risers 50a are actuated in response to tripping of switches (as at 58 in FIG. 2) by lifting of the squeegee rollers 29 and 33 effected by underpassage of sheet 12. In FIG. 2, the switch'is tripped by the trunnion carried by the squeegee roller 29.'

As the sheet trailing end passes, beyond switch tripping squeegee rollers 30, 32 and 34 the latter drop and effect turn-off of liquid flow to the headers, at their as sociated stations, as described. These rollers prevent carry over of dammed liquid to the following stations, as is clear. I

Subsequent treatment of the emulsion surface on the conveyed sheet may advantageously include drying and application of a protective coating, as for example a lacquer layer for waterproofing. FIG. lb shows passage of the sheet through heating means defined by overlying hood or tunnel 60, there being a heater plate or rods 61 beneath of rollers 13 to direct heat radiation upwardly for downward reflection by the metallic hook onto the damp emulsion. Air knives" 62 and 63 precede and follow the heater structure to direct streams of air onto and across the sheet 12, for additional drying and to confine the heating between the knives by air conduction of excess heat away from the apparatus. Each knife comprises a perporated air supply duct 64 extending laterally over the sheet path and contained within a plenum chamber 65. Air released when pressure from the duct into the chamber is delivered via a narrow lateral outlet or slit 66 onto the path of plate travel.

Following such drying of the developer treated coating, a protective layer is applied as by a wick 68 extending laterally over the sheet in FIG. lb. The protective layer may for example consist of a lacquer 69 (as for. example shellac) supplied via a receptacle 70 from the bottom of which the wick extends downwardly. An-

other air knife immediately following the lacquer application delivers warm air streams for drying the lacquer layer, as by driving off volatile solvent.

Finally, the support rollers 13b at the end of the cont-- veyor are not driven by belts 22, but function as idlers. As a result, the conveyed sheet comes to rest overlying the idlers and overhanging the end 74 of the system, 'so

that an operator may then remove the completely treated sheet.

To complete the description of the belt drive, sheaves 75 and 76 turn the belts at opposite ends of their travel,

and the rear sheave may be suitably driven as by a variable speed drive motor 77 coupled to the sheave as by chain drive 78. The motor and other elements of the system may be controlled as from a panel 80.

Generally speaking, and with respect to the emulsion coating 11 on the plate or sheet, known photographic iron processes are usable. These encompass processes in which the original ferric salts or the reduced ferrous salt react with another substance to form a colored reaction product; processes in which the ferrous salt reduces another metallic salt to form a metallic image; and processes based on the ability of ferric salts to render gelatine and other organic colloids insoluble. Blue color is formed as a result of a reaction between the ferrous salt and ferricyanide. The composition of the sensitizing solution may vary widely, and in general it may consist of an aqueous solution of potassium ferricyanide, ferric ammonium citrate, or other complex ferric salt and a polybasic acid such as citric or oxalic. A metal sensitizer may consist of ferric ammonium oxalate, potassium oxalate, oxalic acid, water, gelatine,

wetting agent and formaldehyde. The developer may consist of potassium bichromate and water.

I claim:

1. In apparatus to develop sensitized emulsion coating on a metallic base sheet, the combination comprising:

a. a sequence of sheet conveying rollers rotating to convey the sheet generally horizontally in a forward direction and with the coating exposed vertically,

b. treating means to deliver and direct different liquids into contact with said coating at different stations during sheet forward conveyance, said treating means including header ducting having outlets directed at the path of sheet advancement through said stations, and a source of emulsion developer liquid in communication with said ducting at one of the stations, and a source of rinse liquid in communication with the ducting at at least one other station, there being means at subsequent stations to heat the sheet fordrying same and to subsequently apply a protective layer over the emulsion, and

' roller weight is imposed on the sheet and directly over certain conveying rollers.

2. The combination of claim 1 wherein sheet conveying rollers are spaced apart at said stations to drain excess liquid flowing off the edge of the sheet,

and including collectors beneath said stations to collect said different liquids.

3. The combination of claim 2 including endless flexible traction means extending along said direction for rotating certain of said conveying rollers directly beneath the squeegee rollers.

4. The combination of claim 3 wherein said traction means comprise belts engaging the undersides of end portions of said conveying rollers so as to support the conveying rollers for rotation, there being flat fluorocarbon tracks on which the belts are supported for movement relative thereto and to remain flat directly beneath said end portions of the conveying rollers.

5. The combination of claim 4 including drip rings on the rollers located to intercept drainage of liquid there- 

1. In apparatus to develop sensitized emulsion coating on a metallic base sheet, the combination comprising: a. a sequence of sheet conveying rollers rotating to convey the sheet generally horizontally in a forward direction and with the coating exposed vertically, b. treating means to deliver and direct different liquids into contact with said coating at different stations during sheet forward conveyance, said treating means including header ducting having outlets directed at the path of sheet advancement through said stations, and a source of emulsion developer liquid in communication with said ducting at one of the stations, and a source of rinse liquid in communication with the ducting at at least one other station, there being means at subsequent stations to heat the sheet for drying same and to subsequently apply a protective layer over the emulsion, and means to direct narrow streams of air laterally across the emulsion side of the sheet prior to and following said subsequent stations, c. and multiple squeegees which are spaced in said direction to engage said coating during said conveyance and to confine said different liquids at said different stations during liquid contact with said coating, said squeegees comprising rollers defining the fore and aft limits of said different stations, and guide means guiding the squeegee rollers at opposite ends thereof to float vertically so that squeegee roller weight is imposed on the sheet and directly over certain conveying rollers.
 2. The combination of claim 1 wherein said sheet conveying rollers are spaced apart at said stations to drain excess liquid flowing off the edge of the sheet, and including collectors beneath said stations to collect said different liquids.
 3. The combination of claim 2 including endless flexible traction means extending along said direction for rotating certain of said conveying rollers directly beneath the squeegee rollers.
 4. The combination of claim 3 wherein said traction means comprise belts engaging the undersides of end portions of said conveying rollers so as to support the conveying rollers for rotation, there being flat fluorocarbon tracks on which the belts are supported for movement relative thereto and to remain flat directly beneath said end portions of the conveying rollers.
 5. The combination of claim 4 including drip rings on the rollers located to intercept drainage of liquid therealong toward said belts and tracks.
 6. The combination of claim 1 wherein said source of rinse liquid is in communication with ducting at stations immediately preceding and following said one station. 